It has long been known that cationally-sensitive compounds, particularly epoxide group-containing monomers, can be polymerized by contacting them under polymerizing conditions with acid curing agents, e.g., Lewis acids (or Friedel Crafts catalysts), phenols, inorganic (or mineral) acids, or carboxylic acids. Under the broad term "Lewis acids" is included transition metal and metalloid halides such as BF.sub.3, PF.sub.5, AsF.sub.5, SbF.sub.5, FeCl.sub.3, SnCl.sub.5, SbCl.sub.5, BiCl.sub.4, TiCl.sub.4, etc. and blocked Lewis acids such as boron trifluoride: monoethylamine (MEA), e.g., BF.sub.3 MEA, PF.sub.5 MEA, AsF.sub.5 MEA, and SbF.sub.5 MEA. These and other acid curing agents for polymerizing epoxide group-containing compounds are discussed in Lee and Neville, "Epoxy Resins," McGraw-Hill Book Company, pages 4-57 to 4-70 (1967).
More recently, photoinitators for the polymerization of cationically-sensitive compounds have been described. These photoinitiators are the aromatic onium salts of complex halogen acids, i.e., the aromatic ammonium, phosphonium, iodonium, sulfonium, or selenonium salts of Group VIA elements with a polyhalogen anion of a Group VA element, such as are disclosed in U.S. Pat. Nos. 4,161,478 (Crivello), 4,150,988 (Crivello), 4,231,951 (Smith), and 4,273,668 (Crivello).
U.S. Pat. No. 4,341,658 discloses a catalyst suitable for bringing about the reaction of a phenolic hydroxyl compound with vicinal epoxide group-containing compounds, the catalyst being the reaction product of a solid substrate containing a plurality of ion-exchangeable cations (i.e., the sodium salt of a sulfonated co-polymer of styrene and divinylbenzene) with a polymer containing a plurality of quaternary onium cations associated with a reactive anion (i.e., poly(diallyl dimethyl ammonium chloride)). The reactive anion could also be provided by a polymeric phosphonium or sulfonium salt (see Col. 2, lines 1-3)). Such polymeric salts, not having a halogen containing complex anion would not be a photocatalyst for the polymerization of epoxide group-containing compounds.
U S. Pat. No. 4,279,717 (equivalent to U.K. Pat. No. 2,057,473) discloses a solventless silicone coating composition effective for rendering surfaces non-adherent to other surfaces and which will cure to a final nonadherent state upon brief exposure to ultraviolet radiation comprising an epoxy functional polydiorganosiloxane silicone fluid and an appropriate bisaryl iodonium salt. The appropriate bisaryl iodonium salts are those in which the aryl groups are substituted by "linear alkylate", i.e., dodecyl groups, the presence of which overcomes the failure of salts to dissolve in the silicone fluid and enable them to disperse throughout.